Premium vs. regular gas: Common considerations

By Kijiji Autos
Premium or regular gas

 JJ'Studio -

You pull up to the gas pump and see there is a choice of premium or regular gas. Have you ever wondered what the difference is? Maybe you wondered if premium gas is necessary or worth the extra money. Here are some tips to help you decide which is best for your vehicle :

The difference between premium gas vs. regular gas 

Gases are subject to an octane rating, which measures a fuel’s ability to resist compression. How it works is, with a higher octane level, there is less likelihood of detonation occurring because it can take more compression. In most states, regular gas is rated at 87 and premium gas is rated at 91 or 93. An occasional detonation at the wrong time won’t harm your engine, but if it happens quite a bit, it could contribute to cause your engine’s performance to decline.

Cars that may require premium gas

Most cars are optimized to run on regular gas. Cars that may require high octane premium gas are cars with engines that have high compression ratios or turbochargers that need it for their intended performance, fuel efficiency and emissions. In this case, the extra cost is worth it if you want your engine to perform at its best.

If you use lower octane gas when higher octane is called for, modern vehicles have an Electronic Control Unit that can account for the difference and adjust, but it could be that your horsepower and miles per gallon will go down, while CO2 emissions will increase.

If an older car doesn't get the premium gas that it needs, it might contribue to engine knock, meaning the fuel doesn't burn evenly in the engine's cylinders, causing combustion to occur at the wrong time. This can lead to engine damage. That said, newer cars have sensors monitored by the engine’s computer that help to prevent this. If it only happens occasionally, though, the engine’s computer can adjust the ignition timing, but it isn’t something that should be done too often.

Other factors 

Another thing to consider in gas are detergent additives. These additives help clean your engine for the best performance. Each retailer has its own blend of additives, across all grades of gas. A Top Tier Gasoline standard was established with the help of BMWHondaToyotaVolkswagen and Audi.

This Top Tier Gasoline goes beyond the minimum required EPA requirement and has a higher percentage of detergent additives. A lower concentration of detergent additives might leave more deposits on fuel injectors, intake valves and other engine components, potentially contributing to increased emissions and lower engine performance.


Premium gas costs around 50 cents more a gallon, which certainly adds up. The majority of cars get no benefit from that extra cost, so you could stick to the octane level that is recommended in your owner’s manual. The Federal Trade Commission advised consumers that in most cases, the higher octane gas won’t make your car get better mileage or performance.

If this has you pumped about looking for your next vehicle, browse Kijiji Autos for new and used vehicles in your area. Use the Online Financing listings to find and finance your next car.

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